SOUTH-CENTRAL CALIFORNIA COAST STEELHEAD RECOVERY PLANNING AREA CONSERVATION ACTION PLANNING (CAP) WORKBOOKS THREATS ASSESSMENT SUMMARY

Transcription

1 SOUTH-CENTRAL CALIFORNIA COAST STEELHEAD RECOVERY PLANNING AREA CONSERVATION ACTION PLANNING (CAP) WORKBOOKS THREATS ASSESSMENT SUMMARY Little Sur River estuary, Monterey County Prepared for: Prepared by: NOAA-NMFS Hunt & Associates Biological Southwest Region Consulting Services 735 State Street, Suite Overpass Rd, Suite 108 Santa Barbara, CA Santa Barbara, CA Contact: Mark Capelli Contact: Lawrence E. Hunt (805) (805) June 2008

2 1 South-Central California Coast ESU Steelhead Threats Assessment Methodology Introduction. The Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service (NMFS) contracted with Lawrence E. Hunt of Hunt & Associates Biological Consulting Services to provide technical support in developing Recovery Plans for steelhead (Oncorhynchus mykiss) populations in the South-Central California Coast Steelhead Evolutionarily Significant Unit (ESU) and the Southern California Coast Steelhead ESU. Specifically, Hunt & Associates was tasked with reviewing existing information on steelhead habitat conditions and assessing the magnitude and extent of threats to steelhead and their habitats and developing recovery planning actions across these two ESUs. This document summarizes the results of an assessment of threats and sources of threats to steelhead in the South-Central California Coast Steelhead ESU, which includes coastal steelhead populations in the Pajaro River watershed of Monterey County southward to the Arroyo Grande watershed in southern San Luis Obispo County, California. Recovery action matrices for each watershed in both ESUs are provided in a separate document. Methods. Twenty-two coastal basins, representing 27 drainages, were selected for threats assessment analysis and recovery planning actions in this ESU (see Table 1 in Threats Assessment Summary section). Boughton et al. (2006) identified these watersheds as supporting historical and extant steelhead populations. Information on existing steelhead habitat conditions in the project area was gathered from a broad range of books, peer-reviewed scientific publications, technical reports, federal, state, and local environmental documents, EIR/EISs, management plans, passage barrier assessments, habitat evaluations, and field surveys, as well as specific information given by stakeholders and other interested parties at a series of public workshops held throughout both ESUs in These sources are listed in the bibliography in this document. A separate CAP Workbook was established for each of the 27 component watersheds analyzed in this ESU. The reader is directed to any of these workbooks for the following discussion: The Conservation Action Planning (CAP) Workbook, a relational database developed by The Nature Conservancy to identify conservation targets, assess existing habitat conditions, and identify management issues was used to organize and evaluate the large amount of information on current steelhead habitat conditions and threats to steelhead in these watersheds, as gleaned from widely disparate sources. The CAP Workbook methodology provides a number of benefits in assessing the magnitude and extent of threats to steelhead and their habitats: It can use quantitative and qualitative (i.e., professional judgment) measures of existing habitat conditions; It provides an objective, consistent means for determining changes in the status of each conservation target (steelhead life history stage) over time;

3 2 It provides an objective, consistent way to compare the status of a specific target between watersheds; It provides an overall assessment of a watershed s health or viability and allows objective comparisons to other watersheds; It focuses recovery actions by identifying past, current, and potential threats to steelhead and their habitats; It provides a central repository for documenting current knowledge and assumptions about existing conditions; It can be continually updated as information on the target s biology and/or existing conditions within watersheds change, and; It creates the foundation upon which recovery actions can be monitored and updated, based on changing current conditions. The CAP Workbook process uses available information on the target s biology in an explicit, objective, consistent, credible, and transparent assessment of current habitat conditions. Assessing threats to particular or multiple life stages does not require perfect information. Rather, the CAP Workbook allows the user to input quantitative as well as qualitative (professional judgment) information in order to determine what existing conditions are and what healthy targets should look like. The Workbook is flexible, iterative, and adaptable it uses the best available knowledge at the time, and can be updated as additional information becomes available. CAP Methodology Conservation Targets. The user identifies specific conservation targets for analysis. The conservation targets in this case are steelhead life history stages: egg, fry, smolt, and adult. In an effort to balance the specificity inherent in a life history stage approach, a more general conservation target, Multiple Life Stages, also was established to allow landscape-scale land use and habitat assessment, based on information derived from GIS=based analysis of entire watersheds (see section below describing relationship between Kier Associates and Hunt & Associates CAP Workbook analyses). CAP Methodology KEAs. Assessing the viability or health of a particular conservation target (life history stage) begins with identifying Key Ecological Attributes (KEA) for each target. KEAs are aspects of the conservation target s biology or ecology such that if missing or severely degraded, would result in loss of that target over time. KEAs, such as substrate quality, non-native species, food availability, road density, water quality, etc., were identified for each target and measurable indicators, such as turbidity, water temperature, aquatic invertebrate species richness, presence or absence of non-native predators, miles of road/square mile of watershed, etc., were identified in order to characterize existing conditions in the component watersheds. KEAs were grouped into three categories, based roughly on spatial scale: Size: target abundance (i.e., number of adult steelhead); Condition: a measure of the biological composition, structure, and biotic interactions that characterize the target s occurrence (i.e., generally a local measure of habitat quality or composition), and;

4 3 Landscape Context: an assessment of the target s environment (i.e., landscape-scale processes, such as connectivity, accessibility of spawning habitat; hydrology). CAP Methodology Current Indicators. The range of variation found in each indicator is subdivided into four more or less subjective, but discrete, categories: Poor, Fair, Good, or Very Good. The current condition of a specific indicator, taken from a field measurement, literature source, or professional judgment, is assigned to one of these four discrete rating categories (see the description of indicators used in the CAP steelhead analyses and the justification for these discrete indicator categories in Kier Associates and National Marine Fisheries Service (2008)). Functionally however, there are essentially two states for the indicator as it relates to the species: poor-fair, in which the indicator exceeds or barely meets the requirements for species survival and the population is in danger of extirpation, and good-very good, where habitat conditions are favorable for species persistence. The CAP Workbook can use local-, regional-, and landscape-scale indicators. For example, land use indicators, such as density of roads per square mile of watershed, has been widely employed as a landscape-scale metric of watershed health for salmonids throughout the western United States (see discussion in Kier Associates and NMFS, 2008). These types of landscape-scale metrics were used in the present document to overcome logistical and analytical problems inherent in local-scale metrics of steelhead habitat quality, e.g, water temperature, that exhibit extreme spatial and temporal variation. The conceptual goal of establishing measurable and objective indicators sometimes exceeded current knowledge of existing habitat conditions in the component watersheds. For example, turbidity is an important steelhead habitat indicator. For the steelhead fry life stage, turbidity was defined as the number of days turbidity exceeded 25 NTUs and the poor category was defined as > 30 days during fry development period, while very good was defined as < 10 days during fry development period, with fair and good conditions intermediate between these boundaries. Currently, there is little or no systematic and widespread collection of turbidity data in most of the subject watersheds drainages to permit a useful analysis. In these instances, subjective information, such as observations of mass wasting of slopes, descriptions of point and non-point sediment inputs, etc., were used to qualitatively assess a current condition and rating for this indicator. A key feature of the CAP Workbook process is its ability to use quantitative information as well as professional judgment to assess current habitat conditions. Because the CAP Workbook analysis is iterative, results can be improved as better quantitative information becomes available. CAP Methodology Stresses and Sources of Stress (Threats). The next step in the CAP Workbook analysis is identifying a series of stresses to each steelhead life history stage. These stresses are basically altered KEAs and, ideally, should directly affect the life stage, e.g., degraded hydrologic function, increased turbidity, presence of non-native predators, increased substrate embeddedness). In this CAP Workbook analysis however,

5 4 the GIS-based surrogate variables used for the Multiple Life Stages conservation target actually are sources of stress, not direct stressors on steelhead life stages (e.g., increased road density (a source of stress) contributes indirectly to increased turbidity (a direct stressor). This resulted in some level of redundancy in the analyses. The user assesses the severity (very high, high, medium, or low) and geographic scope (very high, high, medium, and low) of each stress, then the CAP Workbook assigns an overall stress rank (very high, high, medium, or low) to that stress. The CAP Workbook automatically inputs the overall rank of each stress into a table that relates the stress to a series of anthropogenic sources of stress (also called Threats) that have been identified by the user as relevant to that watershed (e.g., roads, grazing practices, logging, recreational facilities, agricultural conversion of watershed lands, dams, groundwater extraction, in-channel mining, etc.). The user ranks each threat on the basis of its relative contribution (very high, high, medium, or low) and irreversibility (very high, high, medium, or low) to each stress (e.g., increased turbidity). The CAP Workbook then ranks the threat (source of stress) as Very High, High, Medium, or Low and inputs that rank into the next step of the analysis. This process was repeated for each conservation target (steelhead life history stage--egg, fry, juvenile, smolt, and adult), as well as the Multiple Life Stages conservation target. CAP Methodology Summary of Threats. The CAP Workbook ranks the threat sources for the various conservation targets (life history stages) from the previous analysis into a Summary of Threats table that lists all the threat sources for all life history stages and assigns a composite Overall Threat Rank to each threat source (e.g., dams and surface water diversions), as well as an overall threat rank to that watershed for all threat sources combined. The Workbook derives a second table ( Stress Matrix ) that shows the rank of each stress on each life history stage. The final step in the steelhead CAP analysis was the derivation of a third table entitled, Overall Viability Summary, that ranks the viability of each life history stage and KEA category (size, condition, and landscape context) by calculating a composite rank of the current habitat indicators from the Viability page of the workbook, as well as an overall Project Biodiversity Health Rank, which is a measure of watershed health based on current habitat conditions. The first and third summary tables proved most useful in analyzing stresses and sources of stress to steelhead in the South-Central California Coast and Southern California Coast steelhead ESUs. Data Gaps. The pages in the CAP Workbooks for the present study have many blank cells. Blank cells indicate a lack of available information. Watersheds that have been intensively studied have fewer blank cells than watersheds with few studies. In general, the level of available information on current watersheds conditions, with a few notable exceptions, increased dramatically south of the Santa Monica Mountains (e.g., the Mojave Rim Biogeographic Population Group watersheds and most of the Orange and San Diego county watersheds). As previously stated, a feature of the CAP Workbook methodology is the ability to update the analyses as information becomes available.

6 5 Relationship between CAP Workbook analyses developed by Hunt & Associates and Kier Associates. The CAP Workbooks analyses prepared by Kier Associates are meant to complement, not duplicate, those prepared by Hunt & Associates. During the initial stages of CAP Workbook analyses by Hunt & Associates, it was determined that, in some cases, surrogate indicators covering regional spatial scales and derived from GIS-based watershed analysis, might be useful in overcoming the spatial and temporal problems associated with habitat indicators that rely on point measurements, such as water temperature, turbidity, riparian corridor width and composition, etc. A separate conservation target category Multiple Life Stages was developed for the CAP Workbook analyses that used GIS-based surrogate indicators as input. Surrogate indicators, such as density of roads per square mile of watershed, density of roads within 300 feet of streams per square mile of watershed, human population density, percent of watershed converted to agriculture; percent of watershed converted to impervious surfaces, percent of watershed burned in past 25 years, and others provided a general measure of existing watershed conditions as they affect multiple steelhead life history stages. For example, road density, especially riparian road density, and percent of watershed as impervious surface, has strong predictive power of general habitat conditions for steelhead because paved surfaces have manifold effects on habitat quality, water quality, and hydrology of streams. Kier Associates was subsequently contracted by NOAA-NMFS to provide GIS-based metrics and values for individual watersheds as support for the CAP Workbook analyses in-progress by Hunt & Associates. Kier Associates analyzed 54 watersheds across both steelhead ESUs (23 in the and 31 in the Southern California Coast Steelhead ESU), using the GIS-based regional indicators. Their workbooks also include information on a small number of point-based measurements, such as dissolved oxygen, water temperature, etc. The Kier Associates workbooks supplement those prepared by Hunt & Associates. Hunt & Associates workbooks are based on review of a large number and broad range of ground-based steelhead surveys, habitat and barrier assessments, and other fieldwork, as well as the GIS-based indicators for the Multiple Life History target category developed by Kier Associates. Hunt & Associates developed CAP Workbooks for 73 watersheds across both steelhead ESUs (27 in the South-Central California Coast Steelhead ESU and 46 in the Southern California Coast Steelhead ESU). Kier Associates workbooks are provided as a separate document (Kier Associates and NMFS, 2008). In order to avoid confusion and explain discrepancies in the overall assessment of steelhead habitat conditions in watersheds found in the present document and Kier Associates document, Table 1 compares the results of the two documents for watersheds in the. It should be noted that the difference between a poor and fair habitat rating or a good and very good rating is often a matter of professional judgment and does not represent important differences in habitat quality. Of real concern, are habitat differences between the poorfair and good-very good indicator categories. Table 1 explains discrepancies between

7 6 poor-fair and good-very good categories between the Hunt & Associates and Kier Associates CAP Workbook analyses. Table 1. Assessment of Overall Habitat Conditions for Steelhead in Component Watersheds in the Between Two CAP Workbook Analyses* Watershed Pajaro River Lower Salinas River Upper Salinas River Carmel River San Jose Garrapata Bixby Little Sur River Big Sur River Willow Salmon San Carpoforo Arroyo de la Cruz Little Pico Pico San Simeon Steelhead Habitat Rating Hunt & Associates Kier Associates Reasons for Discrepancy Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Difference in rating floodplain connectivity and number of available indicators used in analysis Natural barrier (waterfall) in lower reach is limit of anadromy. Kier rates entire watershed as poor on this basis; Hunt & Associates rates only accessible reach. Kier includes point measurements for dissolved oxygen for fry, juvenile, and smolt life stages (rated as poor ); difference in number of available indicators

8 7 Santa Rosa Morro Chorro Los Osos San Luis Obispo Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability Pismo Arroyo Grande Minor difference in cutoff points between indicator categories; difference in number of indicators used to determine steelhead life history stage viability * Overall habitat condition rating taken from Project Biodiversity Health Rank rating in Overall Viability Summary table in Summary section of individual CAP Workbooks (composite rating of habitat conditions for all steelhead life history stages combined). Watersheds analyzed only by Hunt & Associates are not shown. Key: dark green = very good conditions; light green = good conditions; yellow = fair conditions; red = poor conditions. The results of the two analyses closely agree. There are four discrepancies (bolded table entries) that can be explained by the type (point measurements) and lower number of indicators used in each analysis by Kier Associates. This is a consistent difference between Kier Associates and Hunt & Associates workbooks. As the number of indicators decreases, the relative weight given to each indicator in the analysis correspondingly increases, and if these indicators are based on point measurements, such as water temperature or dissolved oxygen, that exhibit extreme spatial and temporal variation, then different results can be obtained. Despite these differences, again, the results closely agree.

9 8 South-Central California Coast Steelhead Recovery Planning Area CAP Workbooks Threats Assessment Summary Location and Component Watersheds. The South-Central California Coast Steelhead Environmentally Significant Unit (ESU) encompasses four Biogeographic Population Groups (BPGs) identified by the NOAA Fisheries Technical Recovery Team for the South-Central/Southern California Coast Steelhead Recovery Domain. These BPGs extend from the southern end of the Santa Cruz Mountains southward through the Coast and Interior Coast ranges to the western end of the Transverse Range, and includes portions of Santa Clara, Santa Cruz, Monterey, San Benito, and San Luis Obispo counties. The component watersheds of the four BPGs analyzed in this document using the CAP analyses are listed in Table 1. Table 1. Component BPGs, Watersheds, and Corresponding CAP Workbooks for the South-Central California Coast Steelhead ESU. Biogeographic Population Group Interior Coast Range Carmel River Basin Big Sur Coast San Luis Obispo Terrace Watershed (North to South) Pajaro River Lower Salinas Basin Upper Salinas Basin Carmel River San Jose Garrapata Bixby Little Sur River Big Sur River Willow Salmon San Carpoforo Arroyo de la Cruz Little Pico Pico San Simeon Santa Rosa Morro Morro Bay Estuary San Luis Obispo Pismo Arroyo Grande CAP Workbook Main stem Pajaro River Uvas Main stem Salinas River Gabilan Arroyo Seco San Antonio River Nacimiento River Carmel River San Jose Garrapata Bixby Little Sur River Big Sur River Willow Salmon San Carpoforo Arroyo de la Cruz Little Pico Pico San Simeon Santa Rosa Morro Chorro Los Osos San Luis Obispo Pismo Arroyo Grande Threats. The type and intensity of land use varies widely across the South-Central California Coast Steelhead ESU. The amount of public ownership of these watersheds, which includes lands managed by the U.S. Forest Service, Bureau of Land Management, California Department of Parks and Recreation, local parks departments, and other public agencies, varies from nearly 100% to 0% of the individual watersheds. In general, the Big Sur Coast BPG watersheds have the greatest amount of land in public ownership.

10 9 However, ownership is not always a predictor of watershed health for steelhead. For example, the Arroyo de la Cruz and Little Pico watersheds have almost no land within their boundaries under public ownership yet provide the highest quality steelhead spawning and rearing habitat of any watershed in this ESU. The Big Sur River, Arroyo Seco, San Antonio River, and Nacimiento River watersheds, with more than half their areas under public ownership, are impacted to varying degrees by recreational, passage barriers, and water management issues. The majority of land in all of the component watersheds across this ESU is open space (78% to 100% of total watershed area). However, the spatial configuration and intensity of land use within these watersheds is what determines the type and magnitude of impacts to steelhead. A relatively small amount of urban or agricultural development can have disproportionately large impacts on instream, riparian, and estuarine habitat conditions for steelhead. The typical pattern of urban and agricultural development concentrates on the flatter portions of a watershed, typically within the floodplain and usually along the main stem of the drainage and one or more tributaries, thereby magnifying potential impacts to steelhead even if the vast majority of the watershed remains undeveloped. Although agricultural conversion of watershed lands in this ESU is small, averaging less than 4% of total watershed area (range = 0% to 19%), agricultural practices are important sources of threats to steelhead. Agriculture situated on the floodplain and flanking the main stem of the drainage frequently leads to loss or degradation of the riparian corridor and frequently channelization. Habitat impairments stemming from agricultural development may range from increased water temperature, incision of the streambed and loss of structural complexity and instream refugia (meanders, pools, undercut banks, etc.), increased sedimentation, turbidity, and substrate embeddedness, and nutrient loading. Urban and suburban development in the watersheds in this ESU also is generally low, averaging 2.8% of total watershed area (range = 0% to 16%). However, population density varies widely between watersheds (Fig. 1; Table 2). High population densities occur in the northernmost watersheds in this ESU, along the main stem of the Salinas River, in the lower Carmel Basin BPG, and in the southern watersheds in the San Luis Obispo Terrace BPG. Coastal watersheds in the center of the ESU (Big Sur Coast and northern San Luis Obispo Terrace BPGs) have very low population densities or are effectively uninhabited (Fig. 1; Table 2).

11 South-Central California Steelhead ESU Human Population Density (persons/sq. mile) Pajaro River Gabilan Arroyo Seco Salinas Basin (upper and lower) San Antonio River Nacimiento River Carmel River San Jose Garrapata Bixby Little Sur River Big Sur River Willow Salmon San Carpoforo Arroyo de la Cruz Little Pico Pico San Simeon Santa Rosa Morro Chorro/Los Osos San Luis Obispo Pismo Arroyo Grande Watersheds (north to south) Figure 1. Habitat conditions and human population density in component watersheds of the (histogram color code is same as for indicator ratings in individual BPG summaries; densities are listed in Table 2).

12 11 Table 2. Human population density of component watersheds in the South-Central California Coast Steelhead ESU (data from CDFFP Census 2000 block data (migrated), 2003). Watershed (north to south) Human Population Density (# / square mile) Interior Coast Range BPG Pajaro River 170 Gabilan 993 Arroyo Seco 3 Salinas River main stem 79 (Salinas Valley) San Antonio River and 6 Nacimiento River combined Carmel River Basin BPG Carmel River 70 Big Sur Coast BPG San Jose 15 Garrapata 6 Bixby 4 Little Sur River 2 Big Sur River 2 Willow 2 Salmon < 1 San Luis Obispo Terrace BPG San Carpoforo < 1 Arroyo de la Cruz < 1 Little Pico 0 Pico 24 San Simeon 19 Santa Rosa 90 Morro, Los Osos, and Chorro 324 creeks combined San Luis Obispo 606 Pismo 160 Arroyo Grande 297 Estuaries are used by steelhead as rearing areas for juveniles and smolt as well as staging areas for smolt acclimating to saline conditions in preparation for entering the ocean and adults acclimating to freshwater in preparation for spawning. Loss and/or degradation of estuarine habitats varied widely across this ESU, averaging about 70% loss in the Interior Coast Range BPG, 33% loss in the Carmel Basin BPG; 15% loss in the Big Sur Coast BPG (almost wholly associated with 98% loss of the San Jose estuary), and; about 43% loss in the San Luis Obispo Terrace BPG. Losses in the latter BPG were concentrated in the southern watersheds (Table 3).

13 12 Table 3. Estuarine habitat loss in component watersheds in the South-Central California Coast Steelhead ESU. Watershed (north to south) Remaining Estuarine Habitat as Percentage of Historic Habitat Interior Coast Range BPG Pajaro River 50 Gabilan 9* Arroyo Seco 9* Salinas River main stem 9 San Antonio River 9* Nacimiento River 9* Carmel River Basin BPG Carmel River 67 Big Sur Coast BPG San Jose 2 Garrapata 100 Bixby 100 Little Sur River 100 Big Sur River 100 Willow 90 Salmon 100 San Luis Obispo Terrace BPG San Carpoforo 80 Arroyo de la Cruz 80 Little Pico 100 Pico 62 San Simeon 50 Santa Rosa 62 Morro 0 Chorro and Los Osos creeks 83 San Luis Obispo 61 Pismo 30 Arroyo Grande 20 * tributary of Salinas River; loss is shared by all contributing sub-watersheds Summary. In general, the overall health of a particular watershed for steelhead is directly related to human population density (Fig. 1). The exception is the large tributaries of the Salinas River. Despite very low population densities and agricultural activity, degraded conditions for steelhead in the Arroyo Seco, San Antonio River, and Nacimiento River watersheds are the result of surface and groundwater management practices designed to serve agricultural development within and outside these watersheds. Dams and other surface water diversions and excessive groundwater extraction are the most pervasive sources of threats to steelhead in this ESU. The Big Sur Coast BPG (with the exception of its northernmost watershed, San Jose ) and the northern watersheds in the San Luis Obispo Terrace BPG, offer the best existing conditions for steelhead.

14 13 Table 4. Severe and Very Severe Sources of Threats to Steelhead in the South-Central California Coast Steelhead ESU *. Biogeographic Population Group Threat Source Interior Coast Range Carmel Basin Big Sur Coast San Luis Obispo Terrace Dams and Surface X X X X Water Diversions Groundwater X X X X Extraction Levees and/or X X X Channelization Urban Development X X X Roads X X X Other Passage X X X Barriers Agricultural Effluent X X X Agricultural X X Development Recreational Facilities X X Flood Control X X Logging X Urban Wastewater X Effluent Non-Native Species X * These are the severe (yellow) and very severe (red) threat sources taken from the top five threat sources identified by the CAP Workbook analyses. See individual BPG Threat Summaries for more information. The individual threat sources listed in Table 4 are not mutually exclusive threat sources and they can create a number of primary and secondary sources of threats to steelhead. For example, dam construction as a result of urban or agricultural development in a watershed not only creates passage barriers to spawning and rearing habitat and negatively affects the natural hydrograph of the affected drainages, recreational development of reservoirs for fishing and camping can impact steelhead by introducing non-native predators and/or competitors (e.g., largemouth bass, crayfish, western mosquitofish) as well as promoting foot traffic within the active channels of contributing streams that can directly affect redds. A widespread trend observed in this ESU is severe to very severe degradation of habitat conditions along the main stem of impaired watersheds, while the upper main stem and tributaries retain relatively high habitat values for steelhead. Because the main stem of these drainages is the conduit that connects steelhead spawning and rearing habitat with the ocean, recovery actions in watersheds impaired in this manner should focus on reducing the severity of anthropogenic impacts along the main stem (resulting from encroachment into riparian areas and related flood control activities) in order to promote connectivity between the ocean and estuarine habitats. Additionally, degraded estuarine conditions stemming from filling, artificial sandbar manipulation, and both point and non-point waste discharges should be further evaluated and addressed as part of any recovery strategy for this ESU (see Threats Summaries and Recovery Action Matrices for individual Biogeographic Population Groups for more specific recovery actions).

15 14 Threats Assessment for the Interior Coast Range Biogeographic Population Group Location and Physical Characteristics. The Interior Coast Range Biogeographic Population Group (BPG) region is the largest of the four BPG regions in the South- Central Coast Steelhead ESU and includes the east-facing (interior) slopes of the Central Coast Range (Santa Lucia Mountains) and the west-facing slopes of the Inner Coast Range (Diablo, Gabilan, Caliente, and Temblor ranges). This region extends 180 miles across the entire length of the South-Central Coast California ESU and includes portions of Santa Clara, San Benito, Monterey, and San Luis Obispo counties. The Interior Coast Range BPG region consists of two major watersheds, the Pajaro River and Salinas River, which empty into the Pacific Ocean at Monterey Bay. The Pajaro River watershed includes the Uvas sub-watershed. The Salinas River watershed is very large, covering over 2.8 million acres (4,426 square miles) and contains two major sub-basins: the Lower Salinas sub-basin, which includes the Gabilan and Arroyo Seco watersheds, and the Upper Salinas sub-basin, which includes the San Antonio River and Nacimiento River watersheds (Fig. 1; Table 1). Tectonic activity associated with the northwest-trending San Andreas Fault has created a parallel series of northwest to southeast-trending basins and ranges in this part of California. The main stem of the Salinas River runs through the center of most of this BPG and two major tributaries, the San Antonio and Nacimiento rivers are unusual in that they flow southward for most of their length before their confluence with the Salinas River, which flows northwest (Fig. 1). Average annual precipitation in this region is relatively low (Table 1) and shows high spatial variability. In general, the higher elevations get more moisture, but because of the rain shadow effect created by the coastal slope of the Central Coast Range, the eastern half of the Interior Coast Range BPG receives significantly less precipitation than the western half. The upper reaches of the Pajaro River watershed extend into the redwood coniferous forests of the Santa Cruz Mountains and receive significantly more rainfall than do other portions of the Interior Coast Range BPG. Although the highly dissected terrain contributes to a very large total stream length in this region (7,773 miles), the majority of drainages exhibit seasonal surface flow or have extensive seasonal reaches because of highly variable patterns of precipitation. Land Use. Table 1 summarizes land use and population density in this region. Although human population density is relatively low for the region as a whole, about 100 persons per square mile, population centers, such as Atascadero, Paso Robles, and Salinas, are growing rapidly and are surrounded by large tracts of semi-developed rural land. Most of the land in the Pajaro River watershed, along the main stem of the Salinas River (Salinas Valley), and throughout the eastern half of the region, is privately owned. Public ownership of land is concentrated in the Los Padres National Forest lands and military reservations, such as Fort Hunter-Liggett and Camp Roberts, situated in the western portions of the Interior Coast Range BPG. Additionally, several rivers have been evaluated for consideration as Federally-designated Wild and Scenic Rivers: Arroyo

16 15 Seco and Tassajara, tributaries to the Salinas River within the Los Padres National Forest. Agriculture (row crop and orchard cultivation and livestock ranching), are important land uses that directly or indirectly affects watershed processes throughout this region. A major consequence of agricultural activity in this region is reservoir development and operation. There are at least 37 dams on watersheds in this region that are large enough to be regulated by the California Department of Water Resources and/or Department of Defense (Fig. 1 shows nine of the more significant dams). These dams are owned and operated by federal, state, public utility, local government, or private interests for irrigation, flood control and storm water management, recreation, municipal water supply, hydroelectric power generation, fire protection, farm ponds, or a combination of these purposes. The largest reservoirs in this region, San Antonio Lake (San Antonio River), Lake Nacimiento (Nacimiento River), and Santa Margarita Lake (Upper Salinas River main stem), receive extensive recreational use. Table 1. Physical and Land Use Characteristics of Watersheds in the Interior Coast Range BPG. Physical Characteristics Land Use Watershed Area (acres/miles 2 ) 1 Stream Length 2 (miles) Average Annual Rainfall 3 (in.) Human Population 4 Public Ownership* Urban Area 5 Agriculture/ Barren 5 Open Space 5 Pajaro River 838,776/1,311 1, ,235 7% 4% 14% 83% Gabilan (99,929)/(156) (247) (18.9) (154,907) (0%) Arroyo Seco (196,430)/(307) (477) (18.5) (920) (58%) Lower Salinas 1,255,902/1,962 2, ,449 14% 3% 19% 78% Basin Upper Salinas 1,576,869/2,464 3, ,805 24% 1% 4% 94% Basin San Antonio (456,758)/(714) (1,030) (17.4) (4,598) (55%) River and Nacimiento River combined Total/Average 3,671,547/5,737** 7,773** ,489** 15%** 3% 12% 85% Sources: 1. CDFFP CalWater 2.2 Watershed delineation, 1999 ( 2. CDFG 1:1,000,000 Routed stream network, 2003 ( 3. USGS Hydrologic landscape regions of the U.S., 2003 (1 km grid cells) 4. CDFFP Census 2000 block data (migrated), CDFFP Multi-source land cover data (v02_2), 2002 (100 m grid cells) ( * National Forest Lands and Military Reservations; does not include State and County Parks ( ** Total or average for Pajaro River watershed (including Uvas sub-watershed), Lower Salinas Basin (including Gabilan and Arroyo Seco sub-watersheds), and Upper Salinas Basin (including San Antonio River and Nacimiento River sub-watersheds)

17 16 Chesbro California Area of Detail Uvas Pickel Sprig Lake Uvas Llagas Pacheco Pacheco Sacramento San Francisco Watsonville Pajaro Arr. Dos Picachos Santa Barbara Los Angeles San Diego Gabilan San Benito River Salinas Monterey Soledad Hernandez Arroyo Seco King City Salinas River San Antonio Nacimiento San Antonio Nacimiento Paso Robles Oncorhynchus mykiss Populations Pajaro Lower Salinas Upper Salinas City Dam Major Rivers Streams County Boundary Lakes Atascadero Santa Margarita Salinas San Luis Obispo 0 25 Miles Figure 1. The Interior Coast Range Biogeographic Population Group region. Seven steelhead populations/watersheds were analyzed in this region: two in the Pajaro River watershed; three in the Lower Salinas Basin, and two in the Upper Salinas Basin.

18 17 Current Watershed Conditions. The relative ratings of current habitat and land use conditions used to assess the suitability of watersheds to support steelhead in the Interior Coast Range BPG are presented in Figure 2. Because of the amount of relevant information available at the time of this analysis, the number of indicators varied widely between watersheds, from five for the San Antonio River watershed to 35 indicators each for the Pajaro and Salinas river main stems. Indicator Ratings No. of Indicators Uvas Pajaro River main stem Salinas River main stem Gabilan Arroyo Seco San Antonio River Nacimiento River Very Good Good Fair Poor Watersheds (North to South) Fig. 2. Relative frequency of indicator ratings for watersheds in the Interior Coast Range BPG. Indicators are rated as Very Good, Good, etc., based on the current condition of landscape, habitat, or population variables. Although the amount of available information (the number of indicators) varies between watersheds, the relative ranking of indicators provides a general picture of existing habitat and land use conditions across the BPG (see individual CAP Workbooks for details). The CAP Workbook analyses rated overall habitat conditions for steelhead as Fair in the Uvas, Gabilan, Arroyo Seco, and Nacimiento River watersheds, and Poor in the Pajaro River, Salinas River, and San Antonio River watersheds. Each of the watersheds included in this BPG are subject to one or more instream, riparian, or upland land use conditions that pose significant threats to steelhead. In general, habitat quality for steelhead declines in a downstream direction through each of these watersheds. The upper watersheds are in relatively good condition; the main stems are in fair to very poor condition. The major concern in this BPG is that the main stems of the two primary drainages in this region, the Pajaro and Salinas rivers, are severely impaired for steelhead by multiple, intensive anthropogenic activities related to agriculture, recreation, and residential development (see Threats discussion below). The main stems of these rivers provide the conduits that connect the ocean, estuary, and upper watershed habitats needed by steelhead to complete their life cycle. In other instances, major tributary watersheds, such as Arroyo Seco and the upper reaches of the San Antonio and Nacimiento rivers, provide generally good to excellent habitat for salmonids, but receive low ratings because they are highly constrained by passage barriers along their lower reaches (dams) or by passage barriers along the main stem of the Salinas River (seasonally dry stream reaches).

19 18 Threats and Sources of Threats. A variable number of threats were used in the CAP Workbooks to determine threat status for the Interior Coast Range BPG watersheds, ranging from seven in the Nacimiento River and San Antonio River watersheds to 16 in the Salinas River main stem (Fig. 3). The level of threat severity is generally very high in all watersheds in this BPG, but especially in Uvas and along the main stems of the Pajaro River and Lower Salinas River (Fig. 3). Threat Ratings Between Watersheds # of Threats Uvas Pajaro River main stem Salinas River main stem Gabilan Arroyo Seco Nacimiento River San Antonio River Low Medium High Very High Watersheds (North to South) Fig. 3. Relative frequency of threat ratings in watersheds in the Interior Coast Range BPG, as identified by the CAP Workbook analyses. The sources, number, and severity of threats varies between watersheds, but watersheds in the Pajaro River and lower Salinas River watersheds are subject to more severe threats than those in the upper Salinas River watershed. Ten anthropogenic activities ranked as the top five sources of stress to steelhead viability in this BPG (Table 2). These sources are not mutually exclusive and can be collapsed into the following general threat categories: barriers to upstream and downstream movement (roads, dams, groundwater extraction, sand and gravel mining); agricultural conversion of floodplain habitats, and; recreational facilities. A pervasive threat to steelhead throughout the Interior Coast Range BPG watersheds is barriers to upstream and downstream passage either in the form of dams and surface water diversions or excessive groundwater extraction that creates and maintains dry stream reaches. As noted previously, there are at least 37 regulated dams on drainages in this watershed. Although there is only one dam on the main stem of the Salinas River, located more than 125 miles from its mouth, the intervening main stem is a major barrier to steelhead passage because extensive reaches routinely go dry in the summer and fall. Dams have isolated native rainbow trout populations in the upper San Antonio and Nacimiento River watersheds that otherwise would be anadromous. The reservoirs created by dams create suitable habitat conditions for several species of non-native fishes and bullfrogs that may affect one or more life history stages of steelhead directly (predation) or indirectly (competition for food). Non-native crayfish, snails, fishes,

20 19 bullfrogs, and even fishes native to California, but not native to the Interior Coast Range BPG, such as Sacramento pikeminnow (= Sacramento squawfish), are problems in particular watersheds. Water management activities are closely related to agricultural conversion of watershed lands. This type of land conversion can increase sedimentation, embeddedness, and turbidity, degrade instream substrates, increase nutrient loading, change riparian canopy cover, and alter the natural hydrograph of the drainages. Anthropogenic activities can produce manifold threats to steelhead. For example, dam construction and groundwater extraction for irrigation and municipal use is directly related to the magnitude of agricultural and urban conversion of floodplain habitats in the Pajaro River and Salinas River watersheds. A consequence of reservoir construction in this BPG is recreation, which generates its own series of impacts, ranging from the purposeful or unintentional introduction of non-native steelhead predators/competitors that have become a severe threat in the Arroyo Seco, San Antonio River, and Nacimiento River watersheds, to ORV damage to instream and riparian habitats that occurs in the lower portions of Arroyo Seco and the main stem of the Salinas River. Another consequence of agricultural and/or urban encroachment onto the floodplains of the Uvas, Pajaro River main stem, Gabilan, and Salinas River main stem is the need to construct levees or otherwise channelize to protect floodplain development. These structures, in turn, require maintenance by flood control agencies which disturbs riparian canopy cover, creates conditions suitable for invasive, non-native plants, and damages instream habitats. Table 2. The top five sources of stress, ranked in order of frequency of occurrence and severity, in the component watersheds of the Interior Coast Range BPG. The Gabilan and Arroyo Seco watersheds also are severely affected by other passage barriers, such as in-channel mining and culverts/road crossings (see CAP Workbooks for individual watersheds for further information). Sources of Threats Dams and Surface Water Diversions Groundwater Extraction Uvas Component Watersheds (north to south) Pajaro River main stem Salinas River main stem Gabilan Arroyo Seco San Antonio River Nacimiento River Agricultural Development Recreational Facilities Levees and Channelization Non-Native Species Urban Development Flood Control Agricultural Effluent Roads

21 20 Other Passage Barriers Key: Threat cell colors represent threat severity, as determined by the CAP Workbook analyses: Red = Very High threat Yellow = High threat Light green = Medium threat Dark green = Low threat Estuarine habitat loss is a pervasive threat to steelhead populations in the Interior Coast Range BPG because, despite its enormous geographic size, the watersheds in this BPG share a single estuarine complex. Today, the mouths of the Pajaro River and the Salinas River at the Pacific Ocean are less than a mile from each other and form separate estuaries, but historically, the lower reaches of these drainages meandered across a broad coastal plain to create a single estuary complex that extended from Watsonville in the north to Marina in the south (Howard, 1979) (Fig. 1). Less than 50% of the Pajaro River estuary remains extant and the Salinas River estuary has been reduced in size by over 91%. Consequently, steelhead populations in far-flung tributaries of the Salinas River, such as Arroyo Seco and the San Antonio and Nacimiento rivers, are subject to equally severe impacts from loss of these estuarine habitats. Fire frequency in the Interior Coast Range BPG is relatively low compared to other BPGs, such as the Santa Monica Mountains BPG, because the western half of the Interior Coast Range BPG, which is the most fire-prone area, is mostly in public ownership and has low population and road density. Wildland fires are not a significant threat source to steelhead in the Pajaro River, Gabilan, and lower Salinas River watersheds, but pose moderate to severe threats in the Arroyo Seco and upper Salinas Basin watersheds, where 15% and 27% of the watershed has burned within the past 25 years, respectively. Here, increased road density allowing increased access to many parts of the watershed, and increased population density in fire-prone areas has increased fire frequency. Improvements to one or a few conditions that are degrading steelhead habitat quality, such as the ineffective Thorne Road Fish Ladder and non-native fish control in the lower reaches of Arroyo Seco, or removing road crossing barriers in portions of the Uvas watershed, could measurably improve conditions for steelhead in relatively localized areas. However, improving conditions for steelhead passage, spawning, and/or rearing over most of the BPG region, i.e., the main stem of the Pajaro River and especially the Salinas River, requires multiple, long-term, measures related to water management, recreation, and fish passage past large dams. The threat sources discussed in this section should be the focus of a variety of recovery actions to address specific stresses on steelhead viability associated with these threats. Spatial and temporal data acquired on specific indicators associated with sources of threats or stresses, such as water temperature, ph, nutrients, etc., are generally inadequate to be the target of specific recovery actions. This type of data acquisition should be the subject of site-specific investigations in order to refine the primary recovery actions or to target additional recovery actions. Impediments to fish passage stemming from the construction and operation of dams and groundwater extractions, modification of channel morphology and adjacent riparian habitats through flood control activities, instream activities such as sand and gravel mining, loss of estuarine functions as a result of filling,

22 21 and point and non-point waste discharges from agricultural and other anthropogenic activities should be further evaluated and addressed as part of any recovery strategy for the Interior Coast Range BPG (see the Recovery Action Matrices for more specific recovery actions).

23 22 ATTACHMENT. SUMMARY TABLES FOR STRESSES AND THREATS, STRESS MATRIX, AND OVERALL VIABILITY SUMMARY FOR THE INTERIOR COAST RANGE BPG

24 23 Threats Assessment for the Carmel River Basin Biogeographic Population Group Location and Physical Characteristics. The Carmel River Basin Biogeographic Population Group (BPG) region is one of the smallest of the four BPG regions; the main axis of the watershed is just 28 miles long. In contrast, the main axis of the neighboring Interior Coast Range BPG region is over 180 miles long. The Carmel River Basin BPG region drains the eastern slopes of the northern portions of the Santa Lucia Range and the western slopes of the Sierra de Salinas in northwestern Monterey County. It empties into the Pacific Ocean at Carmel Bay, just south of the Monterey Peninsula. This BPG region shares some physical characteristics with the Interior Coast Range BPG region, such as general northwest-southeast watershed orientation, landform evolution largely controlled by tectonic activity associated with the San Andreas Fault, and a highly dissected watershed. There are seven major perennial tributaries to the Carmel River, all perennial, (Fig. 1). Average annual precipitation in this region is relatively low (Table 1) and shows high spatial variability. In general, the coastal regions and higher elevations receive higher amounts of precipitation. The Carmel River watershed is relatively steep and most of the tributaries are naturally perennial. Land Use. Table 1 summarizes land use and population density in this region. Human population density is moderately high and concentrated in the lower and middle portions of the Carmel Valley, and includes the towns of Carmel and Carmel Valley. Population density averages 70 persons per square mile of watershed. Although less than 4% of the watershed is classified as urban, well over 50% of the watershed is privately-owned and the Carmel Valley, through which the main stem flows, is surrounded by extensive areas of ranches and rural land use. Less than 1% of the watershed is under cultivation. There are three dams in the Carmel River watershed: the Black Rock on the Black Rock tributary was constructed in 1925 and is used for recreational purposes, the San Clemente Dam, located at stream mile 18.5 at the confluence of San Clemente and the main stem, was constructed in 1921, and the Los Padres Dam, located at stream mile 24.8, was constructed in The San Clemente and Los Padres dams are used for municipal and agricultural water supply. These dams are privately-owned and are regulated by the California Department of Water Resources. Los Padres National Forest lands cover about 31% of the watershed. Additionally, a portion of the lower watershed is owned and managed by the Monterey Peninsula Regional Park District.